Acquisitions (Unaudited) Purchase Price Allocation (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2013	Jun. 03, 2013		Dec. 31, 2012	May 31, 2013 Plains Exploration & Production Company [Member]		Jun. 30, 2013 McMoRan Exploration Co [Member]	Jun. 03, 2013 McMoRan Exploration Co [Member]		May 31, 2013 McMoRan Exploration Co [Member]	Jun. 03, 2013 Eliminations [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Current assets		$ 1,106			$ 1,010			$ 96			$ 0
Oil and natural gas properties - full cost method:
Subject to depletion	12,200	12,248			11,447			801			0
Not subject to depletion	11,400	11,327			9,635			1,692			0
Property, plant, and equipment		262			261			1			0
Investment in MMR		0	[1]		848	[1]		0	[1]	848	(848)	[1]
Other assets		411			12			399			0
Current liabilities		1,089			915			174			0
Debt (current and long-term)		11,250			10,630			620			0
Deferred income taxes		3,871	[2]		3,871	[2]		0	[2]		0	[2]
Other long-term liabilities		1,126			868			258			0
Redeemable noncontrolling interest		1,008			749			259			0
Total fair value, excluding goodwill		7,010			6,180			1,678			(848)
Goodwill	1,904	1,904	[3]	0	454	[3]		1,450	[3]		0	[3]
Total purchase price		$ 8,914			$ 6,634		$ 3,128	$ 3,128			$ (848)
Tax Rate, Fair Value Adjustments, Percent	38.00%
Federal Statutory Income Tax Rate, Percent	35.00%
State Income Taxes, Percent	3.00%

[1] PXP owned 51 million shares of MMR common stock, which was eliminated in FCX's condensed consolidated balance sheet at June 30, 2013.

[2] Deferred income taxes have been recognized based on the estimated fair value adjustments to net assets using a 38 percent tax rate, which reflected the 35 percent federal statutory rate and a 3 percent weighted-average of the applicable statutory state tax rates (net of federal benefit).

[3] The final valuation of assets acquired, liabilities assumed and noncontrolling interest is not complete and the net adjustments to those values may result in changes to goodwill and other carrying amounts initially assigned to the assets, liabilities and noncontrolling interest based on the preliminary fair value analysis.